DE60022913T2 - SOLVING A CONNECTION IN A TWO-LAYER NETWORK - Google Patents

Abstract

The present invention relates to a network element in a communication network layer of a two-layer communication network, the two-layer communication network comprising a first communication network layer adapted to establish a communication channel to a terminal, and a second communication network layer based on Internet protocol and adapted to establish a call to said terminal, the network element in the communication network layer comprising: a decision means configured to decide that at least a part of a connection for a call associated to the terminal is to be released, and a forwarding means configured to forward an indication about said decision to a network element of another communication network layer.

Description

FIELD OF THE INVENTION

The The invention relates to a method for releasing a connection in a two-layer communication network.

BACKGROUND OF THE INVENTION

About the Whole following description means a two-layered one Communication network intended a communication network, the first communication network layer used to set up a communication channel to a terminal that communicates in a call, and to transfer adapted to this call and has a second communication network layer, which is adapted to set up this call. An application layer, as used in the present specification means a designated one Set of security mechanisms, files, data and logs (excluding transfer layer protocols), a call means a logical one shortcut between two or more users or subscribers, while one Communication channel intended a logical connection on the transfer layer between at least two endpoints (eg between a mobile terminal and a support node) means. Naturally If the invention is not restricted to voice calls, the term "call" is intended to be a subset of meetings

One terminal can be any communication endpoint that is for sending and / or Receiving data via a communication channel is adapted. In particular, a terminal may be a wireless terminal or a terminal be that via wires or Lines communicates. Examples of terminals are radio terminals that as a mobile station MS or user equipment UE (a terminal in accordance with UMTS standards, also known as third generation (3G) terminal is), or a server device.

1 shows an example of a basic network architecture for such a two-layer communication network. The illustrated example is given with reference to a UMTS / GPRS network as a first communication network layer adapted for establishing a communication channel to a terminal (UE) communicating in a call and transmitting that call, and one on an internet protocol based IP network as a second communication network layer adapted for establishing a call (eg Internet Protocol telephony IPT). However, networks operating in accordance with other standards may also be selected, as long as the applicability of the invention is not significantly affected thereby.

A subscriber device UE as a terminal communicates with and / or via the communication network. This means that the user equipment UE can communicate with another subscriber device (not shown) or with a server instance (not shown) inside or outside the communication network. An external server instance could again be considered as a terminal. The page initiating the call is called the caller, while the called page is called the called party. The according to 1 The communication network shown is a two-layer communication network consisting of a GPRS / UMTS network as an example of a first communication network layer and an Internet Protocol-based (IP) network as an example of a second communication network layer. At least one interface I / F is present between the first and the second communication network layer. In the illustrated case, a network function instance known as a policy control function (PCF) forms the interface. Nevertheless, the interface may be provided directly between the network layers, ie between corresponding nodes thereof. In such a case, and referring to the illustrated example, the interface between the gateway GPRS support node GGSN and the call state control function CSCF (sometimes referred to as proxy CSCF) would be provided. The CSCF, in turn, is adapted to communicate with other functional entities and elements of the IP network, such as, for example, a home subscriber server HSS (not shown), etc.

On a call communicates with the subscriber device via a Packet data protocol (PDP) context. For the PDP context, a radio bearer (RB) between the user equipment UE and a node_B of a radio access network RAN of the GPRS / UMTS network layer set up. (A node_B corresponds in a GSM network a base station.) The node_B is under the control of a radio network controller RNC (corresponding to a base station controller BSC in GSM). Of course it includes a radio access network generally includes a plurality of Node_B elements. For the Simplicity of the drawings, however, only a Knoten_B was shown. An example of one such radio access network is UTRAN (Terrestrial UMTS RAN).

The radio access network RAN (serving as an example of the access network) also a non-radio access network (ie a wired / fixed access network) is conceivable) is connected to a core network CN. A core network designates the part of the GPRS / UMTS network which is independent of the connection technology of the UE device. In the example shown, the core network is a GPRS (General Packet Radio Service) core network. The core network comprises a service GPRS support node SGSN and a gateway GPRS support node GGSN, these nodes being known as such and a detailed description thereof is therefore considered unnecessary.

It it is assumed that the terminal and / or the subscriber device UE / MS, the / with the over Briefly outlined communication network communicates, GPRS subscribes Has.

One such GPRS subscription includes this Subscription to one or more PDP addresses (packet data protocol). Each PDP address is defined by one or more PDP contexts in the terminal (UE and / or MS), SGSN and GGSN. Each PDP context can use a TFT ("Traffic Flow Template ": Traffic flow template). At any time can at the most a PDP context exists that has the same PDP address in Is related, without him a TFT is assigned. Everyone PDP context exists independently in one of two PDP states (Active / inactive). The PDP state indicates whether data transmission for this PDP address (and TFT) enabled or is activated or not. If all with the same PDP address Deactivated PDP contexts are one data transmission for this PDP address incapable or locked. All PDP contexts of a user or subscriber are for the IMSI ("International Mobile Subscriber Identity ": International mobile subscriber identification) of this subscriber with the same MM context ("Mobility Management": Mobility management) connected.

Of the inactive state identifies the data service for a particular PDP address of the participant as not activated. The PDP context contains none Routing or Mapping information to process PDP PDUs (Protocol Data Units) the to the PDP address belong. It can no data transmitted become.

The terminal (UE and / or MS) initiates a transition from the inactive to the active state by the PDP context activation process is initiated.

in the active state becomes the PDP context for the in-use PDP address in the terminal MS, SGSN and GGSN. The PDP context includes mapping and routing information for transmitting PDP PDUs therefor special PDP address between the terminal (MS) and the GGSN. The active one PDP state is only allowed when the mobility management state the subscriber's readiness, ready, PMM idle or PMM connected. The Iu Interface Radio Access Bearer (RAB) can be used for a active PDP context or not.

One active PDP context for a terminal (MS) is transferred to an inactive state when the Deactivation process is initiated.

at a call release or disconnection of a call of a terminal, the has subscribed to a GPRS network and is currently using the or over the network communicates, situations occur in which the call is terminated, but the PDP contexts are still active. In such a case can be further attempted, data packets to or from the PDP address transferred to, which is related to the still active PDP context.

There the fee collection or calculation of a service for a subscriber on the quantity of data transmitted to or from him or on can be based on time of which the PDP context is active is such a situation for one Participant is not desirable that he will be billed for data services he actually does not used and / or received.

The document WO-A-00/01173 shows such a service.

There the GPRS network only capable is to serve a limited number of subscribers, d. H. dates to forward to a limited number of addresses for which PDP contexts are in an active state is one such Situation with regard to a waste of communication network resources not desirable because other participants through active PDP contexts of participants who actually do not more involved in a reputation could be blocked.

The Document 3G TS23.060 V3.4.0, July 2000, shows both terminal and Network-initiated operations for PDP context deactivation and connection termination in a GPRS environment.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the inventions tion to provide a method for releasing a connection or a part of the connection in a two-layer communication network, wherein the method prevents the occurrence of the aforementioned disadvantages, for. B. unnecessary resource allocation.

According to the invention This task is achieved by a method for releasing at least a part of a connection for a call to a two-layer communication network with a first communication network layer adapted for setup a communication channel to a terminal, and a second communication network layer, which is based on an internet protocol and adapted for setting up the Call to the device, the method comprising the steps of: deciding in one the first and the second communication network layers that at least the part of the connection to be released, which is related to the terminal stands, forwarding the decision from the one of the communication network layers, in which the decision was made, via an interface between the first and the second communication network layer to the others of the communication network layers, and also a step of watching a state of inactivity of the terminal through the first communication network layer, and where in the case a detection of a state of inactivity the decision regarding the release by the first communication network layer and from the first to the second communication network layer is forwarded.

• – ist die erste Kommunikationsnetzwerkschicht ein GPRS/UMTS-System;
• – ist die zweite Kommunikationsnetzwerkschicht ein IP-Multimedia-Teilsystem;
• – ist das Endgerät eine Mobilstation (MS) oder eine Teilnehmervorrichtung (UE);
• – wird die Schnittstelle zwischen der ersten und der zweiten Kommunikationsnetzwerkschicht durch eine Netzwerkfunktionsinstanz gebildet;
• – ist die Netzwerkfunktionsinstanz eine Richtliniensteuerfunktion (PCF);
• – ist die Verbindung eine Sitzung;
• – weist das Verfahren zusätzlich die Schritte auf: Freigeben einer eingerichteten Sitzung zu dem Endgerät, das bei der Sitzung kommuniziert, Modifizieren eines Kommunikationskanals, der für die Sitzung verwendet wird;
• – ist die Modifikation eine Deaktivierung;
• – beeinflusst die Modifikation mindestens einen Parameter eines Satzes von Parametern, die die Verbindung definieren;
• – ist der mindestens eine Parameter der Dienstgüteparameter ”garantierte Bitrate” und wird die garantierte Bitrate derart modifiziert, dass sie auf null gesetzt wird;
• – beeinflusst die Modifikation eine Abrechnung für den Kommunikationskanal;
• – wird der Kommunikationskanal durch Verwendung eines PDP-Kontexts dargestellt;
• – ist die Verbindung eine Sitzung;
• – weist das Verfahren zusätzlich die Schritte auf: Freigeben oder Modifizieren des Kommunikationskanals und Modifizieren der Sitzung, die auf dem Kommunikationskanal transportiert wird;
• – ist die Modifikation eine Freigabe;
• – beeinflusst die Modifikation eine Abrechnung für die Sitzung;
• – wird der Kommunikationskanal durch Verwendung eines PDP-Kontexts dargestellt;
• – weist das Verfahren zusätzlich einen Schritt zum Auffordern des zweischichtigen Kommunikationsnetzwerks durch das Endgerät auf, das Endgerät von der Sitzung freizugeben, und wobei die Entscheidung in Bezug auf die Freigabe von der zweiten Kommunikationsnetzwerkschicht basierend auf der Freigabeanforderung von dem Endgerät getroffen und von der zweiten an die erste Kommunikationsnetzwerkschicht weitergeleitet wird;
• – wird der Untätigkeitszustand durch eine Unterbrechung bei einer Funkverbindung dargestellt.

According to further embodiments of the invention:

• The first communication network layer is a GPRS / UMTS system;
• The second communication network layer is an IP multimedia subsystem;
• The terminal is a mobile station (MS) or a user equipment (UE);
• The interface between the first and the second communication network layer is formed by a network function entity;
• The network function instance is a policy control function (PCF);
• - the connection is a session;
• The method additionally comprises the steps of: enabling an established session to the terminal communicating at the session, modifying a communication channel used for the session;
• The modification is a deactivation;
• The modification influences at least one parameter of a set of parameters defining the connection;
• The at least one parameter of the quality of service parameter is "guaranteed bit rate" and the guaranteed bit rate is modified to be set to zero;
• The modification influences a billing for the communication channel;
• The communication channel is represented by using a PDP context;
• - the connection is a session;
• The method additionally comprises the steps of: enabling or modifying the communication channel and modifying the session transported on the communication channel;
• - the modification is a release;
• - the modification affects a settlement for the session;
• The communication channel is represented by using a PDP context;
• The method additionally comprises a step of requesting the two-layer communication network by the terminal to release the terminal from the session and wherein the decision regarding the release of the second communication network layer is made by the terminal based on the release request from the second terminal the first communication network layer is forwarded;
• - The idle state is represented by an interruption in a radio connection.

The Invention also relates to a communication system with a terminal (UE), the above a connection to a two-layer communication network communicates, the network having a first communication network layer, adapted for establishing a communication channel to the terminal (UE) communicating in the call and a second communication network layer adapted to set up an application layer connection for the Reputation, wherein the system is adapted to perform the method steps for releasing the connection as set forth above.

• 1) Freigeben eines Rufs in der Anwendungsschicht, Andeuten der Ruffreigabe an die Übertragungsschicht, Durchführen spezieller Funktionen in der Übertragungsschicht infolge der Andeutung (z. B. Freigeben des Kommunikationskanals oder Einbeziehen der Andeutung in Abrechnungsinformationen);
• 2) Freigeben eines Kommunikationskanals (d. h. PDP-Kontext) oder eines Teils des Kommunikationskanals (d. h. RAB) in der Übertragungsschicht, Andeuten davon an die Anwendungsschicht, Freigeben des Rufs in der Anwendungsschicht. (Es sollte berücksichtigt werden, dass eine Verbindung bestimmungsgemäß entweder einen Ruf oder einen PDP-Kontext oder einen Teil des PDP-Kontexts (d. h. RAB) meint.)

Consequently, according to the invention:

• 1) releasing a call in the application layer, indicating call release to the transfer layer, performing special functions in the transfer layer as a result of the hint (eg, releasing the communication channel or incorporating the hint in billing information);
• 2) releasing a communication channel (ie PDP context) or part of the communication channel (ie RAB) in the transmission layer, indicating it to the application layer, releasing the call in the application layer. (It should be remembered that a connection is intended to have either a reputation or a PDP context or a part of the PDP Contexts (ie RAB) means.)

Accordingly the invention provides the advantage that each of the communication network layers Aware of the need to share a connection and empowered is, appropriate action to connect to their network layer, to no network capacity for a connection to waste that no longer is active or can be.

Besides that is the terminal from the burden or Last frees to worry about initiating the deactivation of the PDP contexts since this duty has now been transferred to the network.

Further is ensured by virtue of the network initiating PDP context deactivation, that the PDP context is not for other purposes than this reputation is used.

It is thereby enabled that the network z. B. an IP multimedia call without regard to it can release, whether the terminal is able to do this, eg. B. if the terminal is outside a coverage area and / or the transmission quality (quality of service) below a predetermined threshold.

There a call through the network automatically after a predetermined Time period can be released to the subscriber no data packets calculated in vain to its PDP address, which is specified by a still active PDP context.

There a terminal could try the PDP context for Further traffic than the reputation to abuse, is further by Modification / deactivation of the PDP context according to the invention such Abuse prevented or at least detected when the invention is implemented.

BRIEF DESCRIPTION OF THE DRAWINGS

The The foregoing and other objects and advantages of the invention will become apparent with reference to the accompanying description of preferred examples and embodiments in conjunction with the associated Drawings more complete can be seen in which show:

1 1 is a block diagram illustration of a two-layer communication network related to an example of a GPRS / UMTS layer and IPT layer communication network;

2 a signaling scenario of a comparative example; and

3 a signaling scenario of an embodiment of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The The invention will now be explained in more detail with reference to the drawings described.

2 and 3 each illustrate a signaling scenario of signals transmitted between individual network parts and / or network elements. The numbering of the arrows, which represent the signal transmission direction, is representative of the successive transmission of the signals and / or execution of processes over time.

The terminal (UE in 1 ) is represented as a mobile station MS, the radio access network RAN is represented by using UTRAN as an example radio access network, the GPRS network elements SGSN and GGSN are shown individually, the interface between the (first layer) (GPRS / UMTS) communication network and the (IPT) network. ) Second layer communication network is represented by the PCF functional element (policy control function). The IPT layer (second layer) of the two-layer communication network is represented by a proxy CSCF as the network function element of this, which is mainly involved in the invention (so that the other network elements of the IPT layer are omitted from the illustration).

[Comparative Example]

The signaling scenario in connection with a comparative example, which is not covered by the present invention, but which serves to assist a reasonable understanding thereof, is according to 2 shown.

2 illustrates a network initiated PDP context deactivation or change in the PDP context.

In short, the terminal MS initiates the call release. The call release is communicated to the proxy CSCF, which sends a corresponding message to the PCF. The PCF sends the hint, ie a decision, to the GGSN. The GGSN, in response, changes a previous decision, ie, initiates PDP context deactivation or PDP context modification, or makes a change in the PDP context when receiving the indication from the PCF. The change in the PDP context may affect billing. The GGSN then sends a request to the PCF to clear the state information relating to the PDP context.

at Call release is thus an inter-network layer communication involved, over the interface between the communication network layers takes place.

The individual steps of the signaling involved will now be described with reference to FIG 2 explained.

In Step # 1 sends the MS as the terminal a "Bye" message. The "Bye" message will sent to the proxy CSCF, which sends the message in the direction of (not shown) to the communication partner terminal via the Intent to inform the MS to end the call.

In Step # 2, the proxy CSCF sends a "Release" message to the PCF. The PCF ("Policy Control Function ": Policy control function) forms the interface between the two layers of the communication network. This function provides sure that participants have unsolicited or assured traffic characteristics violate or disregard. Consequently, the task of the policy control function in the distribution available Network resources in a defined way via a Amount of network participants involved in these resources compete, and thus serves a connection approval policy to enforce.

In Step # 3 allows the PCF to receive the release message Sending a "Release Test." Message to the Confirm proxy CSCF.

In Step # 4, the PCF sends the "decision" message (with a request ID) to the GGSN for the previous decision to change, d. H. to designate the call release. If (a) PDP context (s) for the ongoing Call in active condition was (were) (what a previous decision corresponds to the PDP context to put into active state) is that made by the PCF Decision (step # 4), in other words, to decide that the PDP context (s), that have something to do with the call to modify or inactive to set (disable).

In Step # 5 allows the GGSN of the PCF to report that it is executing has successfully completed the decision, d. H. the decision in an adequate Implement action by giving the "status report" message (with the request ID) to the PCF.

In the following steps # 6 to # 9, the GGSN initiated PDP context deactivation or modification may be performed. According to 2 the first case is shown. The PDP context deactivation and modification are known as such, so these steps will not be described in more detail. As an alternative to the PDP context deactivation or modification, the GGSN may make a change in the PDP context. The change may affect billing for the PDP context. The functions performed may be network operator specific.

In Step # 10, the GGSN then sends a message "Request State delete "(with the Request ID) to the PCF to clear the request state from the To eliminate PCF.

On Following step # 10, in step # 11, the radio access bearer release process carried out.

It note that in steps # 4 (decision), # 5 (status report) and # 10 (Clear Request State) Messages can be COPS messages. COPS is an IETF ("Internet Engineering Task Force ") specific protocol for a PEP ("Policy Enforcement Point ": Policy enforcement point) for policy information from the PDP ("Policy Decision Point ": Request a directive decision point). It is not Requires that these messages are COPS messages.

It It should also be noted that steps # 2 through # 11 are the same are, if the other communication endpoint (not shown) Call release initiates.

When Alternative to the above-mentioned sequence of signaling steps it is also possible that the PCF may be adapted, the request state information already upon receipt of the call release indication from the proxy CSCF remove. In that case, would the GGSN the message "request state delete "(step # 10) do not have to send resulting in a reduced signaling amount.

[Embodiment]

According to the present embodiment a call such as an IP multimedia call is released through the network, if the terminal MS is prevented or prevented from doing so. This is for example the Case when the MS outside of the service area of the serving node_B and a handover was not successful.

In general, a RAB at a sub or if an inactivity state of an MS has been observed and detected by the first communication network layer.

Short said derives according to the present embodiment the radio network controller RNC the Radio Access Bearer (RAB) enabling process one. Then the RAB is released. The SGSN modifies or deactivates (as a kind of modification) the affected PDP context. The GGSN informs the PCF about the PDP context modification / deactivation. The PCF sends a message to the proxy CSCF to release the affected call or to modify. To release the call, the proxy CSCF sends the message (eg a SIP bye message (SIP = "Session Initiation Protocol ": Session initiation protocol)) to the mobile station MS as the terminal (which is optional is) and to the other communication endpoint. The proxy CSCF can confirmations for this Message received.

consequently RAB sharing involves inter-network layer communication, the above the interface between the communication network layers takes place.

The individual steps of the signaling involved will now be described with reference to FIG 3 explained.

To a certain interruption time at a radio link or after a certain period of inactivity is the network able to release or modify a call, z. B. when the terminal MS has left the supply area. One of the network initiated call release or modification is particularly important if a billing or fee collection for the Reputation based on time.

3 illustrates a call release signaling scenario initiated by the network upon detection of inactivity of the terminal MS.

In Step # 1 detects and / or notices the radio network controller (RNC) that the radio link to the MS has been interrupted or the terminal MS inactive has been. Upon detection of this situation, the RNC sends a message "RAB Release Request" to the SGSN.

In a following step # 2 will be the. Radio Access Bearer Release carried out.

Thereafter, in step # 3, the SGSN modifies and / or deactivates the affected PDP context for the subscriber by sending a "Update PDP Context Request" (in the case of a modification to be explained later) or a "Delete PDP Context Request". (in case of deactivation) to the GGSN. According to 3 the latter case is shown.

As shown in step # 4, the GGSN sends a message "request state delete "(with the Request ID) to the PCF to clear the request state from the To eliminate PCF.

In In response, the PCF sends the "Release" message in step # 5 to the proxy CSCF to request a call release or modification.

As In step # 6, the proxy CSCF can receive the message by sending a "Release Test." message to the Confirm PCF.

In At step # 7, the Proxy CSCF may (optionally) send a "Bye" message send to the terminal, that now z. Outside a supply is located (with this message sent optionally can be, because the terminal, if it's outside of one Supply is not necessarily received, this message can), and can the "bye" message to the (not shown) communication partner of the illustrated terminal Send MS. As an alternative, the proxy CSCF may modify the call (which is not shown). The modification can be a billing or Fee collection for the call influence.

During steps # 8 to # 10 becomes the PDP context deactivation process (which is known as such) carried out.

In Step # 11 can the terminal MS (optional, for example if it is not completely outside a supply and some signaling is still possible) and the (not shown) another endpoint is call release by sending an appropriate acknowledgment message (eg "200 OK "message) to confirm.

According to 3 For example, the message transmitted in step # 4 (clear request state) may be a COPS message.

Either the comparative example as well as the embodiment have been described with regard to to deactivate an affected PDP context for a call described. However, deactivating the PDP context provides one Borderline case of a modification of a PDP context. Accordingly is also a modification of the PDP context instead of deactivation possible.

Such a PDP Context Modification will after a RAB release (with reference to FIG 3 ) and before a RAB release (with reference to 2 ) carried out. As such, the PDP context is maintained in the course of a modification, but the QoS parameter "guaranteed bit rate" (as an example) is set to zero in a modification as conceivable in connection with the invention.

In such a case, the GGSN (in the embodiment) should send the "request" message (with request ID and negotiated QoS as a parameter) to the PCF. Upon receipt of the request message with the (requested) guaranteed bitrate of zero, the PCF should send the "release" message to the proxy CSCF. In connection with the example ( 2 ), however, in the case of modifying PDP contexts instead of deactivating, the PCF should send the "decision" message with content such that the GGSN modifies the affected PDP context such that the guaranteed bit rate is set to zero.

Nonetheless, disabling affected PDP contexts is as described 2 and 3 each shown optimally for the network resources. That is, since the PDP context is used only for the call that the PDP context is no longer needed after release of the call and thus can be deactivated without causing any difficulties.

Regarding 2 In addition, the PDP context deactivation may occur immediately. Optionally, the GGSN may set a timer when the "decision" message is received, and initiate PDP context deactivation after the expiration of the timer.

Regarding 3 In addition, a call release can be made immediately. Optionally, the CSCF may set a timer when the release message is received, and initiate a call release after the expiration of the timer.

above For example, inter-network layer signaling has been described as she over the PCF takes place as an interface network element. Either in the comparative example as well as in the embodiment, the communication between the GGSN and the proxy CSCF, however, without involvement of the PCF network element carried out become. The PCF may be located in the CSCF or in the GGSN. In this case would have however, a new interface between GGSN and (proxy) CSCF is defined become.

consequently becomes either a call or a PDP context through a network layer released, with the release notified to the other network layer becomes. Call release may affect the PDP context used to transport the call. A PDP context release may be the call transported on the PDP context influence. The term "compound" as used herein used above, was chosen to either a call or a PDP context (or even part of the PDP context, d. H. a radio access bearer) to describe while the term "communication channel" a PDP context called.

As Accordingly, the invention accordingly proposes a method for releasing at least part of a connection in a two-layered one Communication network with a first communication network layer, adapted to set up a communication channel to a terminal and a second communication network layer that is adapted for establishing an application layer compound, wherein the method comprising the steps of: deciding in one of the first and the second Communication network layer that at least the part of the connection is free to share, which is related to the terminal, forwarding the decision of one of the communication network layers, in which the decision was made, via an interface between the first and the second communication network layer to the others of the communication network layers, and also a step of watching a state of inactivity of the terminal through the first communication network layer, and where in the case a detection of a state of inactivity the decision regarding the release by the first communication network layer and from the first to the second communication network layer is forwarded. Accordingly, each communication network layer has Aware of the need to share a connection and is capable of taking appropriate action to avoid wasting network capacity for a call, not longer is active or can be.

The The invention also relates to a correspondingly working or operated communication network.

Even though the invention hereinbefore with reference to its preferred Examples and embodiments it should be understood that many Modifications to this can be made without departing from the scope of the invention departing. It is intended that all such modifications in the scope of the associated claims fall.

Claims (21)

Method for releasing at least one part a connection for a call to a two-layer communication network with a first communication network layer, which is adapted to Establishing a communication channel to a terminal, and a second communication network layer, on an internet protocol is based and adapted for establishing the call to the terminal, in which the method comprises the steps of: Decide in one of the first and second communication network layers that at least the Part of the connection is related to the terminal in connection stands, Forwarding the decision from the one of the communication network layers, in which the decision was made, via an interface between the first and the second communication network layer to the other of the communication network layers, and further one Step of monitoring a state of inactivity of the terminal through the first communication network layer, and where in the case a detection of a state of inactivity the decision regarding the release by the first communication network layer and from the first to the second communication network layer is forwarded. Method according to claim 1, in which the first communication network layer is a GPRS / UMTS system is. Method according to claim 1, in which the second communication network layer is an IP multimedia subsystem. Method according to claim 1, where the terminal a mobile station (MS) or a user equipment (UE). Method according to claim 1, in which the interface between the first and the second communication network layer is formed by a network function instance. Method according to claim 5, where the network function instance is a policy control function (PCF) is. Method according to claim 1, where the connection is a session. Method according to claim 7, in addition with the steps: To share an established session the terminal, that communicates at the meeting, Modifying a communication channel, the one for the Session is used. Method according to claim 8, where the modification is a deactivation. Method according to claim 8, in which the modification is at least one parameter of a sentence influenced by parameters that define the connection. Method according to claim 10, in which the at least one parameter of the quality of service parameters "guaranteed Bitrate "is and the guaranteed bit rate is modified to be on Zero is set. Method according to claim 8, where the modification affects billing for the communication channel. Method according to claim 8, in which the communication channel by using a PDP context is pictured. Method according to claim 1, where the connection is a session. Method according to claim 14, in addition with the steps: Enabling or modifying the communication channel, and Modify the session on the communication channel is transported. Method according to claim 15, where the modification is a release. Method according to claim 15, where the modification affects billing for the session. Method according to claim 15, in which the communication channel by using a PDP context is pictured. Method according to claim 7, in addition with a step of Requesting the two-layer communication network through the terminal, the terminal release from the session, and where the decision in Relating to the release of the second communication network layer based on the release request made by the terminal and forwarded from the second to the first communication network layer becomes. Method according to claim 1, in which the inactive state is represented by an interruption in a radio connection. Communication system with a terminal (UE), that at a call over a connection to a two-layer communication network communicates, the network having a first communication network layer, adapted for establishing a communication channel to the at the call communicating terminal (UE), and a second communication network layer which is based on an internet protocol and adapted is for establishing the call to the terminal, the system being adapted is the method steps for releasing the connection according to a the claims 1 to 20.